Introduction

SPECTRUM is a stellar spectral synthesis program designed for use on a wide range of platforms, including most types of UNIX and Linux. SPECTRUM can be used to calculate a synthetic stellar spectrum given a stellar atmosphere model and certain other inputs. SPECTRUM carries out this computation under the assumption of local thermodynamic equilibrium (LTE). Currently, SPECTRUM is suitable for computing stellar spectra in the spectral-type range B - mid M.

SPECTRUM may be programmed with command-line switches to give a number of different output formats. For example, in default mode, SPECTRUM computes the disk-integrated normalized intensity spectrum, but with the appropriate switches, SPECTRUM can be directed to compute either the specific intensity from any point on the stellar surface or the disk-integrated flux. SPECTRUM currently supports all naturally occurring elements, along with a total of 308 isotopes. Hyperfine structure can also be accommodated. In addition, SPECTRUM can handle 12 diatomic molecules, including TiO, which are important in stellar spectra. Isotopic versions of these molecules are also supported.

SPECTRUM comes with a suite of supporting programs, including programs for computing elemental abundances from equivalent widths (ABUNDANCE), a program for determining abundances and the microturbulent velocity simultaneously (BLACKWEL), a program that aids in the identification of stellar spectral lines (LINES), and various other auxiliary programs to convert the output of SPECTRUM to a form that can be compared directly with observations.

Note: This documentation is written specifically for versions 2.75 and later.